Engine Diagnostic Code 21?!

[joshy0077]

Hi all,

I just did the engine diagnostic procedure on my 92 ES and found that I apparently have a bad 02 sensor. Check engine light came on a few days ago...now I'd like to fix the problem. Can anyone instruct me on how to go about changing the 02 sensor? I plan on running up to Autozone today to buy a new one. Thanks in advance!

[Toysrme]

Code 21 is the bank #1 o2 sensor.

Bank 1 is the rear bank.

Because the wires get very old and brittle, I suggest finding, and unplugging the contector FIRST, before yanking on anything.

You unbolt it (two 10mm bolts if I remember correctly).

The replacement sensor should look like this, just newer.

You should buy two and change the front sensor also. If you look around online, you can find them for as low as $25. Universal sensors oughta cost about $35.

Be sure to put on the new gasket.

After changing, remove the EFI fuse (box clsoes to battery) count to one, and replace it. The ECU will be reset.

[joshy0077]

Hey Toysrme thanks for the quick reply...just a few questions.

1.) I was up at both Autozone and Murray's Disc. Auto and both stores were charging about $90 for the OEM O2 sensor, and Autozone was charging $35 for universal. At Murray's, they had a $90 and a $30 sensor, one was for before cat. converter, one was for after. Which do I need, and should I buy from a store or online?

2.) I'm not sure where exactly the O2 sensors go, any pics on the location? (Sorry if that sounds very inane)

3.) If I do buy the universal O2 sensor, Autozone said I would have to splice the wires and then tape them together...I've never seen an O2 sensor, so are there multiple wires or what? In your pictures it looks like just one wire...but I'm not sure.

Thanks again!

[SKperformance]

What check engine procedure did you do?

The obd-1

or the HVAC system saying the solar sensor is not registering any light?

[joshy0077]

I did the OBD1 procedure, not really sure what its called, bridged the diagnostic fuses with a paper clip, then watched the check engine blinks to get the code.

[Toysrme]

converter, one was for after. Which do I need, and should I buy from a store or online?

Before the cat. Unless you have the extremely rare CA emession 3vz-fe, it has no post cat o2 sensor.

You can buy wherever you want too, o2 sensors are o2 sensors!

I'm not sure where exactly the O2 sensors go, any pics on the location? (Sorry if that sounds very inane)

They bolt onto the exhaust manifolds.

Sorry, I don't have a better picture.

If I do buy the universal O2 sensor, Autozone said I would have to splice the wires and then tape them together...I've never seen an O2 sensor, so are there multiple wires or what? In your pictures it looks like just one wire...but I'm not sure.

It's a single wire.

[joshy0077]

Any chance you can draw a quick arrow on that picture so I can get an idea as to where the sensor is?

When I asked about the store vs. online, I just was wondering whether the price was so much less online that it would be worth it to buy it from there, or if the price that an autoparts store offered was a good price.

Thanks again!

[Toysrme]

The front o2 sensor (bank 2 sensor 1 - code 28) is the pink arrow.

The one you have problems with is the rear manifold on the back side of the engine. You'll have to wiggle your hand behind the engine to get to it.

*edit* My bad... Forgot the link!

[joshy0077]

Hey Toys, thanks a lot for the help! You're engine is so clean looking...how'd you do that?

[joshy0077]

One more quick question... After looking for prices online, I saw many different kinds of sensors...and I didn't know which to buy, is my car California Emission or Federal/Canada Emission? How can I tell which it is? I found both O2 sensors...which I feel pretty good about :D , but now I just need to find out which ones to buy. It looks like it could be very difficult to install the rear sensor from the top of the engine..but maybe going from underneath is easier?